$ brew install git

$ brew install ruby

$ brew install node

Error: You have not agreed to the Xcode license. Please resolve this by running:
  sudo xcodebuild -license

$ sudo xcodebuild -license

function update {
    set -ex

    npm update -g
    npm cache clean

    update_rubygems
    gem update bundler
    gem cleanup

    brew update
    brew upgrade
    brew cleanup

    echo "Update complete!!"
}